The invention relates to providing telephony services in communications networks.
Data networks are widely used to link various types of nodes, such as personal computers, servers, gateways, network telephones, and so forth. Networks may include private networks, such as local area networks and wide area networks, and public networks, such as the Internet. The increased availability of such data networks has improved accessibility among nodes coupled to the data networks. Popular forms of communications across such data networks include electronic mail, file transfer, web browsing, and other exchanges of digital data.
With the increased capacity and reliability of data networks, voice and multimedia communications over data networks have become possible. Such forms of communications include telephone calls over the data networks, video conferencing, and distribution of multimedia data (such as by multicast).
Various standards have been proposed for voice and multimedia communications over data networks. For example, a multimedia data and control architecture has been developed by the Internet Engineering Task Force (IETF). The protocols that are part of the IETF multimedia data and control architecture include a Session Initiation Protocol (SIP) for establishing call sessions; a Resource Reservation Protocol (RSVP) for reserving network resources; a Real-Time Transport Protocol (RTP) for transporting real-time data and providing quality of service (QoS) feedback; a Real-Time Streaming Protocol (RTSP) for controlling delivery of streaming media; a Session Announcement Protocol (SAP) for advertising multimedia sessions by multicast; and a Session Description Protocol (SDP) for describing multimedia sessions.
In a communications system that provides for voice or other streaming communications, various types of telephony or call services may need to be defined to process and respond to call requests. A communications network may include various elements, such as a voice mail system, an integrated voice response (IVR) system, media gateways, and so forth, that may be involved in a given call session. Creation of applications to handle various services that may be part of a call session needs to account for interactions among the network elements.
A need thus exists for a convenient and efficient method and apparatus to provide for telephony services in a communications network.